Android开发之利用ListView动态刷新某个Item

2019-12-12 04:14:25

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前言

本文实现的是使用ViewHolder来刷新某项数据，而不用每次都全部刷新数据。下面话不多说，来看看详细的介绍。

实现方法

继承BaseAdapter，新建ViewHolder类。

public class TestListAdapter extends BaseAdapter {  private Context mContext;   private List<String> strList;   public TestListAdapter(Context context, List<String> list) {   super();   this.mContext = context;   this.strList = list;  }   @Override  public int getCount() {   // TODO Auto-generated method stub   return strList.size();  }   @Override  public Object getItem(int position) {   // TODO Auto-generated method stub   return position;  }   @Override  public long getItemId(int position) {   // TODO Auto-generated method stub   return position;  }   @Override  public View getView(int position, View convertView, ViewGroup parent) {   // TODO Auto-generated method stub   ViewHolder holder = null;   if (null == convertView) {    convertView = LayoutInflater.from(mContext).inflate(R.layout.line, null);     holder = new ViewHolder();    holder.iDText = (TextView) convertView.findViewById(R.id.textView_id);    holder.strText = (TextView) convertView.findViewById(R.id.textView_str);     convertView.setTag(holder);   } else {    holder = (ViewHolder) convertView.getTag();   }    holder.iDText.setText(position + "");   String str = strList.get(position);   holder.strText.setText(str);    return convertView;  }   private static class ViewHolder {   private TextView iDText;    private TextView strText;  }   public void updataView(int posi, ListView listView) {   int visibleFirstPosi = listView.getFirstVisiblePosition();   int visibleLastPosi = listView.getLastVisiblePosition();   if (posi >= visibleFirstPosi && posi <= visibleLastPosi) {    View view = listView.getChildAt(posi - visibleFirstPosi);    ViewHolder holder = (ViewHolder) view.getTag();     String txt = holder.strText.getText().toString();    txt = txt + "++;";    holder.strText.setText(txt);    strList.set(posi, txt);   } else {    String txt = strList.get(posi);    txt = txt + "++;";    strList.set(posi, txt);   }  } }

在Activity中，调用updateView()方法，刷新数据。

public class MainActivity extends Activity {  private MainActivity mContext;   private EditText idEdit;   private TextView textView;   private List<String> strList = new ArrayList<String>();  private ListView listView;  private TestListAdapter ListAdapter;  @Override  protected void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   setContentView(R.layout.activity_main);    mContext = this;    for (int i = 0; i < 100; i++) {    strList.add("test data");   }    idEdit = (EditText) findViewById(R.id.edittext_id);   textView = (TextView) findViewById(R.id.textview_modify);    listView = (ListView) findViewById(R.id.listview);   ListAdapter = new TestListAdapter(mContext, strList);   listView.setAdapter(ListAdapter);    //动态刷新   textView.setOnClickListener(new OnClickListener() {     @Override    public void onClick(View v) {     // TODO Auto-generated method stub     String idStr = idEdit.getText().toString();     int idInt = Integer.parseInt(idStr);     ListAdapter.updataView(idInt, listView);//动态修改    }   });  } }

给出布局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:background="#FFFFFF"  android:orientation="vertical" >   <LinearLayout   android:layout_width="match_parent"   android:layout_height="40dp"   android:orientation="horizontal" >    <EditText    android:id="@+id/edittext_id"    android:layout_width="200dp"    android:layout_height="wrap_content"    android:hint="put modify id" />    <TextView    android:id="@+id/textview_modify"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="动态修改"    android:textColor="#123456" />  </LinearLayout>   <ListView   android:id="@+id/listview"   android:layout_width="match_parent"   android:layout_height="wrap_content" >  </ListView>  </LinearLayout>

总结

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